Funds are requested to expand and supplement a largely prospective study of the total medical care costs of (i.e., all inpatient and out patient costs) of persons with AIDS incurred over a 12-month period (or until the patient dies) for (1) patients treated at San Francisco General Hospital (SFGH), (2) patients treated by 23 San Francisco community phusicians who agreed to participate in the study, and (3) a random sample of 50 to 75 AIDS patients treated at the Kaiser-Permanente Health Plan facility in San Francisco. We have enrolled 91 patients of community physicians and 49 patients treated at SFGH. We expect that by the end of March 1987, we will have complete data on the use of and expenses for medical services for a 9-month period (or until the patient died) for about 82 of these patients. On enrollment, these patients were handed a brochure which explained the study and contained a consent form, a patient's bill of rights, a short questionnaire, and a lisst on which they were asked to record the names and addresses of the medical care providers form whom they had received serv ices during the preceeding three months and to sign it to give us permission to contact these providers for copies fo their bills. The patients are then recontacted with such a form at three-month intervals until data are obtained for a 12-month period (or until the patient dies). Still to be obtained from the Kaiser-San Francisco organization are the medical utilization data for the Kaiaser AIDS patients. The principal aim of the study is to secure data for a 12-month period on total use of and expenses for medical services by persons with AIDS (something no study to date has attempted), on the type of services for which they were incurred, and on the sources of payment for medical care. A secondary aim is to explore possible differences in the use of medical resources for the treatment of AIDS between three different types of medical care providers: a public hospital (SFGH, the county and city hospital), physicians in private practice in the community, and a health maintenance organization (Kaiser-Permanente).